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==Overview==
==Overview==
Pituitary [[apoplexy]] is an acute [[clinical]] [[syndrome]] caused by [[hemorrhage]] and [[necrosis]] in the [[pituitary gland]]. Most commonly [[pituitary apoplexy]] is associated with [[pituitary adenoma]]. The [[pituitary adenoma]] predisposes to an increased risk of [[bleeding]] within the [[pituitary gland]]. The [[pituitary adenoma]] has [[Fenestrated membrane|fenestrated]] [[endothelium]] surrounded by a variable number of [[smooth muscle cells]], which are not found in normal [[pituitary gland]].
Pituitary apoplexy is an acute [[clinical]] [[syndrome]] caused by [[hemorrhage]] and [[necrosis]] in the [[pituitary gland]]. Most commonly, pituitary apoplexy is associated with [[pituitary adenoma]]. [[Pituitary adenoma]] predisposes the patient to an increased risk of [[bleeding]] within the [[pituitary gland]]. [[Pituitary adenoma]] has [[Fenestrated membrane|fenestrated]] [[endothelium]] surrounded by a variable number of [[smooth muscle cells]] which are not found in the normal [[pituitary gland]], leading to increased susceptibility to pituitary apoplexy in these [[tumors]]. Pituitary apoplexy can result from a [[mutation]] in [[AIP (gene)|AIP gene]] which is a [[tumor suppressor gene]] located on [[chromosome]] 11q13.2. On gross pathology, pituitary apoplexy presents with [[hemorrhage]] with or without [[necrosis]]. [[Electron microscopy]] shows evidence of abnormal [[fenestration]] of tumor [[vessels]] ([[pituitary adenoma]]) with fragmented [[basal membrane]]<nowiki/>s that may predispose the patient to [[hemorrhage]].


==Pathophysiology==
==Pathophysiology==
Pituitary [[apoplexy]] is caused by bleeding into [[pituitary gland]]. Most often, pituitary [[apoplexy]] is seen with a [[pituitary adenoma]]. Pituitary adenoma has an increased risk of [[bleeding]] within the [[pituitary gland]].  
Pituitary apoplexy is caused by bleeding into the [[pituitary gland]]. Most often, pituitary apoplexy is seen with a [[pituitary adenoma]]. [[Pituitary adenoma]] predisposes the patient to an increased risk of [[bleeding]] within the [[pituitary gland]].<ref name="pmid16487443">{{cite journal |vauthors=Nielsen EH, Lindholm J, Bjerre P, Christiansen JS, Hagen C, Juul S, Jørgensen J, Kruse A, Laurberg P |title=Frequent occurrence of pituitary apoplexy in patients with non-functioning pituitary adenoma |journal=Clin. Endocrinol. (Oxf) |volume=64 |issue=3 |pages=319–22 |year=2006 |pmid=16487443 |doi=10.1111/j.1365-2265.2006.02463.x |url=}}</ref><ref name="pmid12577104">{{cite journal |vauthors=Chacko AG, Chacko G, Seshadri MS, Chandy MJ |title=Hemorrhagic necrosis of pituitary adenomas |journal=Neurol India |volume=50 |issue=4 |pages=490–3 |year=2002 |pmid=12577104 |doi= |url=}}</ref><ref name="pmid15531524">{{cite journal| author=Zayour DH, Selman WR, Arafah BM| title=Extreme elevation of intrasellar pressure in patients with pituitary tumor apoplexy: relation to pituitary function. | journal=J Clin Endocrinol Metab | year= 2004 | volume= 89 | issue= 11 | pages= 5649-54 | pmid=15531524 | doi=10.1210/jc.2004-0884 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15531524  }} </ref><ref name="pmid25859802">{{cite journal| author=Oldfield EH, Merrill MJ| title=Apoplexy of pituitary adenomas: the perfect storm. | journal=J Neurosurg | year= 2015 | volume= 122 | issue= 6 | pages= 1444-9 | pmid=25859802 | doi=10.3171/2014.10.JNS141720 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25859802  }} </ref><ref name="pmid5055626">{{cite journal| author=Schechter J| title=Ultrastructural changes in the capillary bed of human pituitary tumors. | journal=Am J Pathol | year= 1972 | volume= 67 | issue= 1 | pages= 109-26 | pmid=5055626 | doi= | pmc=2032586 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=5055626  }} </ref><ref name="pmid3417848">{{cite journal| author=Schechter J, Goldsmith P, Wilson C, Weiner R| title=Morphological evidence for the presence of arteries in human prolactinomas. | journal=J Clin Endocrinol Metab | year= 1988 | volume= 67 | issue= 4 | pages= 713-9 | pmid=3417848 | doi=10.1210/jcem-67-4-713 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3417848  }} </ref><ref name="pmid18372348">{{cite journal |vauthors=Nawar RN, AbdelMannan D, Selman WR, Arafah BM |title=Pituitary tumor apoplexy: a review |journal=J Intensive Care Med |volume=23 |issue=2 |pages=75–90 |year=2008 |pmid=18372348 |doi=10.1177/0885066607312992 |url=}}</ref><ref name="pmid6256408">{{cite journal |vauthors=Findling JW, Tyrrell JB, Aron DC, Fitzgerald PA, Wilson CB, Forsham PH |title=Silent pituitary apoplexy: subclinical infarction of an adrenocorticotropin-producing pituitary adenoma |journal=J. Clin. Endocrinol. Metab. |volume=52 |issue=1 |pages=95–7 |year=1981 |pmid=6256408 |doi=10.1210/jcem-52-1-95 |url=}}</ref>
* [[Pituitary adenoma]] has [[Fenestrated membrane|fenestrated]] [[endothelium]] surrounded by a variable number of [[smooth muscle cells]], which are not found in normal [[pituitary gland]].     
* [[Pituitary adenomas|Pituitary adenoma<nowiki/>s]] have decreased [[blood]] supply and [[angiogenesis]].
* A [[pituitary adenoma]] has [[Fenestrated membrane|fenestrated]] [[endothelium]] surrounded by a variable number of [[smooth muscle cells]], which are not found in the normal [[pituitary gland]].     


* [[Vascular endothelial growth factor|VEGF]] [[Messenger RNA|mRNA]] may be increased in pituitary tumors, especially in non-functioning pituitary adenomas, which could be related to an abnormal vascularization.
* [[Vascular endothelial growth factor|VEGF]] [[Messenger RNA|mRNA]] may be increased in [[pituitary tumors]], especially in non-functioning [[pituitary adenomas]], which could be related to an abnormal [[vascularity]].


* Enlarging [[pituitary adenoma]] may outgrow their blood supply, making them susceptible to [[bleeding]] and [[infarction]].  
* Enlarging [[pituitary adenoma|pituitary adenomas]] may outgrow their [[blood]] supply, making them susceptible to [[bleeding]] and [[infarction]].  


* The [[bleeding]] may lead to increase in [[intrasellar]] [[pressure]]. The increased [[intrasellar]] [[pressure]] may compress the adjoining structures and lead to clinical symptoms of pituitary apoplexy.<ref name="pmid15531524">{{cite journal| author=Zayour DH, Selman WR, Arafah BM| title=Extreme elevation of intrasellar pressure in patients with pituitary tumor apoplexy: relation to pituitary function. | journal=J Clin Endocrinol Metab | year= 2004 | volume= 89 | issue= 11 | pages= 5649-54 | pmid=15531524 | doi=10.1210/jc.2004-0884 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=15531524  }} </ref>
* The [[bleeding]] may lead to increase in [[intrasellar]] [[pressure]]. The increased [[intrasellar]] [[pressure]] may compress the adjoining structures and lead to the clinical [[symptoms]] of pituitary apoplexy.
* In addition, these [[adenoma|pituitary adenoma]]<nowiki/>s have decreased blood supply and [[angiogenesis]].<ref name="pmid25859802">{{cite journal| author=Oldfield EH, Merrill MJ| title=Apoplexy of pituitary adenomas: the perfect storm. | journal=J Neurosurg | year= 2015 | volume= 122 | issue= 6 | pages= 1444-9 | pmid=25859802 | doi=10.3171/2014.10.JNS141720 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=25859802  }} </ref><ref name="pmid5055626">{{cite journal| author=Schechter J| title=Ultrastructural changes in the capillary bed of human pituitary tumors. | journal=Am J Pathol | year= 1972 | volume= 67 | issue= 1 | pages= 109-26 | pmid=5055626 | doi= | pmc=2032586 | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=5055626  }} </ref><ref name="pmid3417848">{{cite journal| author=Schechter J, Goldsmith P, Wilson C, Weiner R| title=Morphological evidence for the presence of arteries in human prolactinomas. | journal=J Clin Endocrinol Metab | year= 1988 | volume= 67 | issue= 4 | pages= 713-9 | pmid=3417848 | doi=10.1210/jcem-67-4-713 | pmc= | url=https://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=3417848  }} </ref>
** An enlarged [[Pituitary adenoma|pituitary tumor]] may become impacted at the diaphragmatic notch, leading to compression of the [[Hypophysis|hypophyseal]] stalk and its [[vascular]] supply.
** An enlarged pituitary tumor may become impacted at the diaphragmatic notch, leading to compression of hypophyseal stalk and its [[vascular]] supply.
** This may render the anterior [[pituitary gland]] and its [[tumor]] with reduced [[blood]] supply causing [[ischemia]] and subsequent [[necrosis]].
** This may render the anterior pituitary gland and its tumor with reduced blood supply causing [[ischemia]] and subsequent [[necrosis]].
** [[Reperfusion]] after [[infarction]] may lead to [[hemorrhage]] within the [[pituitary gland]] or [[Pituitary adenoma|adenoma]].
** [[Reperfusion]] after infarction may lead to [[hemorrhage]] within the [[pituitary gland]] or adenoma.


==Genetics==
==Genetics==
*Gene involved in the [[pathogenesis]] of pituitary apoplexy include [[mutation]] in AIP gene, which is located on [[chromosome]] 11q13.2.
*[[Gene]] involved in the [[pathogenesis]] of pituitary apoplexy include a [[mutation]] in [[AIP (gene)|AIP gene]], which is located on [[chromosome]] 11q13.2.
*The most common [[mutation]] site in AIP gene is p.R304 locus.
*The most common [[mutation]] site in the AIP gene is p.R304 locus.
*Mutated AIP loses its activity as a [[Tumor suppressor gene|tumor supressor gene]] and leads to increased [[proliferation]].
*[[Mutated]] AIP loses its activity as a [[Tumor suppressor gene|tumor suppressor gene]] and leads to increased [[Cell (biology)|cell]] [[proliferation]].
*The penetration of AIP postive carriers is 12-30%.
*The penetration of AIP positive carriers is 12-30%.


==Associated Conditions==
==Associated Conditions==
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*The predominant finding is [[hemorrhage]] with or without [[necrosis]].
*The predominant finding is [[hemorrhage]] with or without [[necrosis]].
*Pale, [[necrotic]] material is particularly found when there is a long interval between the acute clinical event and [[surgery]].
*Pale, [[necrotic]] material is particularly found when there is a long interval between the acute clinical event and [[surgery]].
[[File:Pituitary apoplexy Gross.png|center|400px]]


==Microscopic Pathology==
==Microscopic Pathology==
Electron microscopic shows evidence of abnormal [[fenestration]] of tumor vessels ([[pituitary adenoma]]) with fragmented [[basal membrane]]<nowiki/>s that may predispose to [[hemorrhage]].
[[Electron microscopy|Electron microscopic]] shows evidence of abnormal [[fenestration]] of [[tumor]] [[vessels]] ([[pituitary adenoma]]) with fragmented [[basal membrane]]<nowiki/>s that may predispose the patient to [[hemorrhage]].


[[File:Nonfunctioning pituitary adenoma (1).jpg|center|400px|Histopathological image of nonfunctioning pituitary adenoma. Hematoxylin & eosin stain showing basophilic appearance of the cells.|alt=Histopathological image of nonfunctioning pituitary adenoma. Hematoxylin & eosin stain showing basophilic appearance of the cells.]]
[[File:Webp.net-resizeimage.jpg|center|Histopathological image of nonfunctioning pituitary adenoma. Hematoxylin & eosin stain showing basophilic appearance of the cells. Source: By Jensflorian (Own work) [CC BY-SA 3.0 (<nowiki>http://creativecommons.org/licenses/by-sa/3.0</nowiki>)], via Wikimedia Commons |alt=Histopathological image of nonfunctioning pituitary adenoma. Hematoxylin & eosin stain showing basophilic appearance of the cells.|frame]]


==References==
==References==
{{reflist|2}}
{{reflist|2}}


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Latest revision as of 16:21, 18 October 2017

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Akshun Kalia M.B.B.S.[2]

Overview

Pituitary apoplexy is an acute clinical syndrome caused by hemorrhage and necrosis in the pituitary gland. Most commonly, pituitary apoplexy is associated with pituitary adenoma. Pituitary adenoma predisposes the patient to an increased risk of bleeding within the pituitary gland. Pituitary adenoma has fenestrated endothelium surrounded by a variable number of smooth muscle cells which are not found in the normal pituitary gland, leading to increased susceptibility to pituitary apoplexy in these tumors. Pituitary apoplexy can result from a mutation in AIP gene which is a tumor suppressor gene located on chromosome 11q13.2. On gross pathology, pituitary apoplexy presents with hemorrhage with or without necrosis. Electron microscopy shows evidence of abnormal fenestration of tumor vessels (pituitary adenoma) with fragmented basal membranes that may predispose the patient to hemorrhage.

Pathophysiology

Pituitary apoplexy is caused by bleeding into the pituitary gland. Most often, pituitary apoplexy is seen with a pituitary adenoma. Pituitary adenoma predisposes the patient to an increased risk of bleeding within the pituitary gland.[1][2][3][4][5][6][7][8]

Genetics

Associated Conditions

Pituitary apoplexy is seen with 0.6 to 10% of pituitary adenomas.

Gross Pathology

  • The predominant finding is hemorrhage with or without necrosis.
  • Pale, necrotic material is particularly found when there is a long interval between the acute clinical event and surgery.

Microscopic Pathology

Electron microscopic shows evidence of abnormal fenestration of tumor vessels (pituitary adenoma) with fragmented basal membranes that may predispose the patient to hemorrhage.

Histopathological image of nonfunctioning pituitary adenoma. Hematoxylin & eosin stain showing basophilic appearance of the cells.
Histopathological image of nonfunctioning pituitary adenoma. Hematoxylin & eosin stain showing basophilic appearance of the cells. Source: By Jensflorian (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons

References

  1. Nielsen EH, Lindholm J, Bjerre P, Christiansen JS, Hagen C, Juul S, Jørgensen J, Kruse A, Laurberg P (2006). "Frequent occurrence of pituitary apoplexy in patients with non-functioning pituitary adenoma". Clin. Endocrinol. (Oxf). 64 (3): 319–22. doi:10.1111/j.1365-2265.2006.02463.x. PMID 16487443.
  2. Chacko AG, Chacko G, Seshadri MS, Chandy MJ (2002). "Hemorrhagic necrosis of pituitary adenomas". Neurol India. 50 (4): 490–3. PMID 12577104.
  3. Zayour DH, Selman WR, Arafah BM (2004). "Extreme elevation of intrasellar pressure in patients with pituitary tumor apoplexy: relation to pituitary function". J Clin Endocrinol Metab. 89 (11): 5649–54. doi:10.1210/jc.2004-0884. PMID 15531524.
  4. Oldfield EH, Merrill MJ (2015). "Apoplexy of pituitary adenomas: the perfect storm". J Neurosurg. 122 (6): 1444–9. doi:10.3171/2014.10.JNS141720. PMID 25859802.
  5. Schechter J (1972). "Ultrastructural changes in the capillary bed of human pituitary tumors". Am J Pathol. 67 (1): 109–26. PMC 2032586. PMID 5055626.
  6. Schechter J, Goldsmith P, Wilson C, Weiner R (1988). "Morphological evidence for the presence of arteries in human prolactinomas". J Clin Endocrinol Metab. 67 (4): 713–9. doi:10.1210/jcem-67-4-713. PMID 3417848.
  7. Nawar RN, AbdelMannan D, Selman WR, Arafah BM (2008). "Pituitary tumor apoplexy: a review". J Intensive Care Med. 23 (2): 75–90. doi:10.1177/0885066607312992. PMID 18372348.
  8. Findling JW, Tyrrell JB, Aron DC, Fitzgerald PA, Wilson CB, Forsham PH (1981). "Silent pituitary apoplexy: subclinical infarction of an adrenocorticotropin-producing pituitary adenoma". J. Clin. Endocrinol. Metab. 52 (1): 95–7. doi:10.1210/jcem-52-1-95. PMID 6256408.

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